What holding pattern direction should a pilot use when cleared to hold south on the one eight zero radial from the ABC VORTAC?

When a pilot is cleared to hold on a specific radial from a VORTAC, the holding pattern is established relative to the radial being used for the hold. In this scenario, the instruction is to hold south on the one eight zero radial.

To visualize this, the one eight zero radial means the aircraft needs to fly directly along a 180-degree line from the VORTAC. In a standard holding pattern, the pilot will maneuver to enter the hold in such a way that they can complete a circuit around the holding fix. Since the hold is established south of the VORTAC on the 180-degree radial, the aircraft would need to turn to the left to exit the holding pattern and subsequently return to it.

This means that for a hold to the south on the 180-degree radial, the proper protocol is to perform left turns. This is consistent with standard holding patterns designed to provide a systematic and safe means of maintaining aircraft separation and orientation relative to the navigation fix. Thus, left turns are the correct choice for this holding pattern.